This invention relates to a film saving apparatus for a photographic camera, especially in the type of camera for producing 3-dimensional prints on lenticular material.
In producing a 3-dimensional print on a lenticular print film, a series of photographs are taken of a subject field from different angles of view by a multilens camera as described, for example, in U.S. Pat. Nos. 3,895,867 and 4,037,950 to Lo et al. The negatives in the series are printed on film covered with a lenticular screen to form lineiform images of the subject. A camera of the type described in the patents takes a series of photographs at laterally spaced vantage points to record a series of exposures, for example, at least four negatives that constitute a group for producing one 3-dimensional print. A problem associated in the taking of the series of negatives is that if one negative or a portion of the negative is incomplete, the entire group is unsuitable in the production of a 3-dimensional print. To this end it is essential that the photographic film not be wasted by winding more than is necessary onto the take-up roll. Frequently, due to habit or otherwise, the operator of the camera may unintentionally wind more film onto the take-up spool as the camera is being loaded thereby loosing one or more prints due to film wastage.
In accordance with the present invention, a film saving apparatus is used in conjunction with the camera for preventing the waste of photographic film and insuring that maximum film is available for producing as many prints as is possible from a single roll of film. The invention has application to any camera using conventional 35 mm roll film or any other roll film because it enables maximum use of the roll film in producing prints. Thus the inventive apparatus by saving film enables the operator of the camera to take as many pictures as possible from a single roll of film and is significant improvement over existing photographic cameras from this standpoint alone.
In the past there have been various devices for threading film onto a take-up spool in a camera by guiding the leader of the roll film to effectuate easy loading and advancement of the film along its film path. For example, U.S. Pat. No. 3,481,260 to Ettischer et al discloses a camera wherein the improvement comprises auxiliary winding means for operatively interconnecting the covered door and the take-up spool for rotating the take-up spool to wind film thereon when the covered door is moved from its open position to its closed position. U.S. Pat. No. 3,377,935 to Furusawa discloses a take-up spool with projecting pawls adapted to intersect the path of the film path as the film is being inserted into the camera with the pawls engaging perforations on the film to effectuate automatic loading of the camera. U.S. Pat. No. 3,479,938 to Winkler et al discloses a camera with automatic film threading mechanism including a deflector which is spring-loaded to be properly positioned with regard to the leading edge of the film being inserted into the camera. U.S. Pat. No. 3,567,147 to Engelsmann et al discloses a camera wherein the inlet of the take-up chamber is adjacent to the discharge end of the film channel and there is a narrow gap for automatically directing the leader of the film toward, and through, the inlet of the take-up chamber. U.S. Pat. No. 3,465,657 to Welzel et al discloses a take-up spool for a camera that automatically guides the film onto the take-up spool. U.S. Pat. No. 4,274,726 to Yoneyama et al discloses automatic film winder including a pressing chamber for guiding the film in the proper manner to effectuate easy loading and accurate advancement thereof. None of these patents contemplates saving film as envisioned by the instant invention.